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Mathematical Problems in Engineering
Volume 2014, Article ID 712418, 11 pages
http://dx.doi.org/10.1155/2014/712418
Research Article

Effects of AC Coils Parameters on Transduction Efficiency of EMAT for Steel Plate Inspection

School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China

Received 23 July 2014; Accepted 8 September 2014; Published 28 September 2014

Academic Editor: Zhiqiang Hu

Copyright © 2014 Xiaochun Song and Yawu Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In order to improve the transduction efficiency of electromagnetic acoustic transducer (EMAT) for steel plates inspection, the constitutive equation of magnetostrictive material was theoretically derived and simplified while the magnetostrictive force is parallel to the material surface. Based on the multiphysics field FEM, the effects of such excitation parameters as current, frequency, and pulse number in AC coils on magnetostrictive strain were mainly simulated, and the influence of the coil with different winding shapes on magnetostrictive strain was also analyzed. The simulation and experimental results indicate that magnetostrictive strain increases with a continuously increasing excitation current density, but it decreases with the increase of the frequency and pulse number of AC currents. Moreover, on condition that loop length and AC currents are held constant, spiral type coils have higher transduction efficiency than homocentric squares and figure-of-eight coils.